Biosensors

14 pages, 3112 KiB

Open AccessArticle

Optical–Electronic Skin Based on Tea Polyphenol for Dual Signal Wearable Sensing

by Jia-Li Xu, Guangyao Zhao, Jiachen Wang, An Tang, Jun-Tao Liu, Zhijie Zhu, Qiang Zhang and Yu Tian

Biosensors 2025, 15(5), 281; https://doi.org/10.3390/bios15050281 (registering DOI) - 29 Apr 2025

Abstract

The rapid development of smart electronic skin has led researchers to design a variety of flexible and stretchable devices that can be used to monitor physiological and environmental signals. In this work, we successfully demonstrate a color-adjustable and conductive wearable optical–electronic skin (OE-skin) [...] Read more.

The rapid development of smart electronic skin has led researchers to design a variety of flexible and stretchable devices that can be used to monitor physiological and environmental signals. In this work, we successfully demonstrate a color-adjustable and conductive wearable optical–electronic skin (OE-skin) based on photonic crystal hydrogel that is capable of delivering both optical and electrical signal responses synchronously. The OE-skin is fabricated by incorporating a structural colored layer, composed of periodically aligned magnetic nanoparticles, into a polyacrylamide hydrogel matrix that contains tea polyphenols and borax. The dynamic boronate ester bonds formed between borax and the catechol groups of tea polyphenols are able to enhance the mechanical properties of the OE-skin, while also conferring excellent electrical conductivity, high sensitivity, and a rapid electrical response. Additionally, the tea polyphenols, which are natural active compounds derived from tea, possess diverse bioactive properties, thereby endowing the OE-skin with excellent antibacterial and biocompatibility characteristics. In addition, the developed electronic skin successfully demonstrates its capability in synergistic electronic and optical sensing during human motion monitoring, indicating broad application prospects in the field of smart wearable sensors. Full article

(This article belongs to the Special Issue Advanced Bioelectronics for Healthcare Monitoring and Disease Diagnosis)

31 pages, 3943 KiB

Open AccessReview

Biosensors for Early Detection of Parkinson’s Disease: Principles, Applications, and Future Prospects

by Panpan Jiang, Nan Gao, Gang Chang and Yuxiang Wu

Biosensors 2025, 15(5), 280; https://doi.org/10.3390/bios15050280 (registering DOI) - 29 Apr 2025

Abstract

Parkinson’s disease (PD), a neurodegenerative disorder marked by the progressive loss of dopaminergic neurons in the substantia nigra, imposes substantial economic burdens, including both direct and indirect costs. The medical community currently lacks a definitive cure for Parkinson’s disease, and early detection is [...] Read more.

Parkinson’s disease (PD), a neurodegenerative disorder marked by the progressive loss of dopaminergic neurons in the substantia nigra, imposes substantial economic burdens, including both direct and indirect costs. The medical community currently lacks a definitive cure for Parkinson’s disease, and early detection is crucial for timely intervention and disease management. As innovative diagnostic tools, biosensors have shown great potential in detecting PD at its early stages. This review comprehensively summarizes recent advances in biosensors for the early detection of PD, with a particular focus on the detection of two key biomarkers: dopamine (DA) and α-synuclein (α-syn). Furthermore, it illustrates a variety of nanotechnology-based biosensors, including optical, electrochemical, and transistor biosensors, detailing their underlying principles, advantages, limitations, and applications in PD detection. Moreover, the review explores the challenges and prospects of advancing biosensors for early PD diagnosis. Full article

(This article belongs to the Section Biosensors and Healthcare)

16 pages, 1900 KiB

Open AccessArticle

Experimental and in Silico Studies on the Development of an Electrochemical Biosensor for the Quantification of H₂O₂ Based on the ChOx Enzyme

by Elvis Ortiz-Santos, Gabriela Valdés-Ramírez, Cesar Millán-Pacheco, Iris N. Serratos, Maria Luisa Lozano-Camargo, Pablo Dalmasso, Gustavo A. Rivas and Laura Galicia

Biosensors 2025, 15(5), 279; https://doi.org/10.3390/bios15050279 - 29 Apr 2025

Abstract

This work presents the development of a biosensing platform for hydrogen peroxide (H₂O₂) electrochemical reduction. The developed platform uses a multi-walled carbon nanotube paste (PMWCNT) and the enzyme cholesterol oxidase (ChOx). The supramolecular architecture of the PMWCNT/ChOx platform was [...] Read more.

This work presents the development of a biosensing platform for hydrogen peroxide (H₂O₂) electrochemical reduction. The developed platform uses a multi-walled carbon nanotube paste (PMWCNT) and the enzyme cholesterol oxidase (ChOx). The supramolecular architecture of the PMWCNT/ChOx platform was characterized using cyclic voltammetry, electrochemical impedance spectroscopy, and amperometry. The results indicated that the presence of ChOx enhances the sensitivity of electrochemical detection for H₂O₂ by 21 times compared to that without ChOx. The designed electrochemical sensing bio-platform for H₂O₂ shows a sensitivity of 26.15 µA/mM in the linear range from 0.4 to 4.0 mM, an LOD of 0.43 µM, and an LOQ of 1.31 µM. Furthermore, in silico studies (molecular dynamics simulations, molecular docking assays, and binding free energy calculations (ΔG_b)) were carried out to characterize and validate the molecular interaction between ChOx and H₂O₂. The computed data confirmed that the binding is spontaneous, and the type of labile interaction promotes a rapid electrochemical reduction of H₂O₂. Full article

(This article belongs to the Special Issue Recent Developments in Nanomaterial-Based Electrochemical Biosensors)

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12 pages, 1517 KiB

Open AccessArticle

Anti-Adalimumab Antibodies Purified from Juvenile Idiopathic Arthritis Patients: Kinetic Characterization Among Biosimilars

by Andrea Di Santo, Edoardo Marrani, Carmen Gallo, Fosca Errante, Valerio Maniscalco, Anna Maria Papini, Gabriele Simonini, Paolo Rovero and Feliciana Real Fernandez

Biosensors 2025, 15(5), 278; https://doi.org/10.3390/bios15050278 - 29 Apr 2025

Abstract

The use of adalimumab biosimilars has become increasingly common in clinical practice, reflecting their growing acceptance and efficacy as therapeutic alternatives to reference biologics. However, studies investigating the molecular interactions between anti-adalimumab antibodies (AAA) elicited in patients and different adalimumab biosimilars remain limited. [...] Read more.

The use of adalimumab biosimilars has become increasingly common in clinical practice, reflecting their growing acceptance and efficacy as therapeutic alternatives to reference biologics. However, studies investigating the molecular interactions between anti-adalimumab antibodies (AAA) elicited in patients and different adalimumab biosimilars remain limited. This study aims to characterize the kinetic interactions between purified AAA from pediatric patients with Juvenile Idiopathic Arthritis and three adalimumab formulations: the originator Humira^®, and the biosimilars GP2017 (Hyrimoz^®) and SB5 (Imraldi^®). For this purpose, adalimumab formulations were immobilized on a gold chip, and purified AAA were flowed to perform further kinetic analysis using the surface plasmon resonance (SPR) technology. Results showed that the K_D values for purified AAA from patients treated with biosimilars GP2017 (Hyrimoz^®) or SB5 (Imraldi^®) were comparable across all formulations tested, including the originator Humira^®. AAA interacted with Humira^®, Hyrimoz^®, and Imraldi^® with similar apparent affinity (10⁻⁹ M > K_D > 10⁻¹⁰ M); slight variations have been observed among patients, less among biosimilars. The similarity in K_D values across biosimilars and the originator supports the notion that, at the level of immunogenicity, biosimilars can be considered clinically comparable to the originator. Full article

(This article belongs to the Special Issue Trends and Perspective of Advanced Nanotechnology for Bio-Sensing, Imaging and Cancer Therapy)

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29 pages, 3459 KiB

Open AccessReview

Aptamer and Oligonucleotide-Based Biosensors for Health Applications

by Beatriz Mayol, I. Zeina Qubbaj, Julieta Nava-Granados, Katherine Vasquez, Scott T. Keene and Juliane R. Sempionatto

Biosensors 2025, 15(5), 277; https://doi.org/10.3390/bios15050277 - 29 Apr 2025

Abstract

Aptamers have emerged as powerful molecular recognition elements for biosensing applications, offering high specificity, stability, and adaptability. This review explores key considerations in designing aptamer-based sensors (aptasensors), with a focus on biomarker selection, aptamer design, and detection and immobilization strategies. However, challenges such [...] Read more.

Aptamers have emerged as powerful molecular recognition elements for biosensing applications, offering high specificity, stability, and adaptability. This review explores key considerations in designing aptamer-based sensors (aptasensors), with a focus on biomarker selection, aptamer design, and detection and immobilization strategies. However, challenges such as biofluid stability and reversibility must be addressed to improve biosensor performance. In this study, the potential of aptamer-based platforms in diagnostics is explored, emphasizing their advantages and future applications. Looking ahead, advances in multifunctional aptamers, integration with nanomaterials, and computational optimization are highlighted as promising directions for enhancing their effectiveness in biosensing. Full article

(This article belongs to the Special Issue Aptamer and Oligonucleotide-Based Electrochemical Biosensors for Environmental Analysis)

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14 pages, 1276 KiB

Open AccessArticle

Thermally Responsive Alkane Partitions and a Magnetofluidic Assay for Point-of-Sample Detection of Viruses in Wastewater

by Miso Na, David J. Boegner, Micaela L. Everitt and Ian M. White

Biosensors 2025, 15(5), 276; https://doi.org/10.3390/bios15050276 - 29 Apr 2025

Abstract

Detecting, identifying, and tracking genetic material in wastewater allows public health agencies to accurately monitor the spread of infectious diseases in communities. In response to the COVID-19 pandemic, viral diagnostics for wastewater have been used to track the spread of SARS-CoV-2 and other [...] Read more.

Detecting, identifying, and tracking genetic material in wastewater allows public health agencies to accurately monitor the spread of infectious diseases in communities. In response to the COVID-19 pandemic, viral diagnostics for wastewater have been used to track the spread of SARS-CoV-2 and other viruses and have allowed public health officials to make more informed decisions regarding public safety. However, due to the cost and complexity of viral RNA/DNA detection platforms, analysis is limited to sophisticated laboratory facilities, which limits deployment and delays results. In contrast, a low-cost rapid point-of-sample solution for the detection of viruses in wastewater would enable worldwide deployment with immediate analytical results. We have recently reported the development of thermally responsive alkane partitions (TRAPs) for automated magnetofluidic assays, enabling sample-to-answer point-of-care detection of viruses in complex samples. Here we demonstrate the use of TRAPs in combination with hydrogel-coated magnetic particles for virus purification and assay automation to enable detection of SARS-CoV-2 from spiked wastewater samples in a low-cost cassette within a handheld instrument. Using this system, we show distinguishable detection of SARS-CoV-2 below 200 copies/mL in wastewater. Full article

(This article belongs to the Section Environmental Biosensors and Biosensing)

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17 pages, 824 KiB

Open AccessReview

DNA Sensors for the Detection of Mercury Ions

by Feng Li, Jinxin Lin, Eric Lichtfouse, Haifeng Qi, Lang Peng, Yangyang Yu and Li Gao

Biosensors 2025, 15(5), 275; https://doi.org/10.3390/bios15050275 - 29 Apr 2025

Abstract

Ecosystem pollution by mercury ions (Hg²⁺) is a major health concern, yet classical analytical methods for mercury analysis are limited. This paper reviews the advances in Hg²⁺ detection using DNA as recognition elements in the sensors. DNA as a recognition [...] Read more.

Ecosystem pollution by mercury ions (Hg²⁺) is a major health concern, yet classical analytical methods for mercury analysis are limited. This paper reviews the advances in Hg²⁺ detection using DNA as recognition elements in the sensors. DNA as a recognition molecule is inexpensive, simple, and appropriate for real-time detection of Hg²⁺. This paper discusses the DNA-based sensors that were used for the detection of Hg²⁺. These can be carried out by electrochemistry, field effect transistors (FET), Raman spectroscopy, colorimetry, and fluorescence resonance energy transfer (FRET). The detection principles and the advantages of DNA in these sensors are also revealed. Finally, the paper provides an overview of prospects and potential challenges in the field. Full article

(This article belongs to the Special Issue Aptamer-Based Nanosensing Strategy and Applications)

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11 pages, 4512 KiB

Open AccessArticle

Fluorescence Lifetime Multiplexing with Fluorogen-Activating FAST Protein Variants and Red-Shifted Arylidene–Imidazolone Derivative as Fluorogen

by Aidar R. Gilvanov, Ivan N. Myasnyanko, Sergey A. Goncharuk, Marina V. Goncharuk, Vadim S. Kublitski, Daria V. Bodunova, Svetlana V. Sidorenko, Eugene G. Maksimov, Mikhail S. Baranov and Yulia A. Bogdanova

Biosensors 2025, 15(5), 274; https://doi.org/10.3390/bios15050274 - 29 Apr 2025

Abstract

Fluorescence-lifetime imaging microscopy (FLIM) is a powerful technique for highly multiplexed imaging in live cells. In this work, we present a genetically encoded FLIM multiplexing platform based on a combination of fluorogen-activating protein FAST and red-shifted fluorogen N871b from the arylidene–imidazolone family. We [...] Read more.

Fluorescence-lifetime imaging microscopy (FLIM) is a powerful technique for highly multiplexed imaging in live cells. In this work, we present a genetically encoded FLIM multiplexing platform based on a combination of fluorogen-activating protein FAST and red-shifted fluorogen N871b from the arylidene–imidazolone family. We showed that a series of FAST protein mutants exhibit similar steady-state optical properties in complex with N871b fluorogen but have different fluorescence lifetimes. The similar brightness and binding strength of pairs of these FAST protein variants with N871b allows them to be successfully used for multiplexing up to three intracellular structures of living cells simultaneously. Full article

(This article belongs to the Section Optical and Photonic Biosensors)

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18 pages, 3935 KiB

Open AccessArticle

Respiration Signal Pattern Analysis for Doppler Radar Sensor with Passive Node and Its Application in Occupancy Sensing of a Stationary Subject

by Chenyan Song, Ehsan Yavari, Xiaomeng Gao, Victor M. Lubecke and Olga Boric-Lubecke

Biosensors 2025, 15(5), 273; https://doi.org/10.3390/bios15050273 - 27 Apr 2025

Viewed by 68

Abstract

Doppler radar node occupancy sensors are promising for applications in smart buildings due to their simple circuits and price advantage compared to quadrature radar sensors. However, single-channel sensitivity limitations may result in low sensitivity and misinterpreted motion rates if the detected subject is [...] Read more.

Doppler radar node occupancy sensors are promising for applications in smart buildings due to their simple circuits and price advantage compared to quadrature radar sensors. However, single-channel sensitivity limitations may result in low sensitivity and misinterpreted motion rates if the detected subject is at or close to “null” points. We designed and tested a novel method to eliminate such limits, demonstrating that passive nodes can be used to detect a sedentary person regardless of position. This method is based on characteristics of chest motion due to respiration, found via both simulations and experiments based on a sinusoidal model and a more realistic model of cardiorespiratory motion. In addition, respiratory rate variability is considered to distinguish a true human presence from a mechanical target. Sensor node data were collected simultaneously with an infrared camera system, which provided a respiration signal reference, to test the algorithm with 19 human subjects and a mechanical target. The results indicate that a human presence was detected with 100% accuracy and successfully differentiated from a mechanical target in a controlled environment. The developed method can greatly improve the occupancy detection accuracy of single-channel radar-based occupancy sensors and facilitate their adoption in smart building applications. Full article

(This article belongs to the Section Biosensors and Healthcare)

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16 pages, 5366 KiB

Open AccessArticle

Understanding the Mechanism of Bent DNA Amplifying Sensors Using All-Atom Molecular Dynamics Simulations

by Kaitlin Bullard, Deborah Okyere, Shelbi J. Foster, Asmaa A. Sadoon, Jiali Li, Jingyi Chen and Yong Wang

Biosensors 2025, 15(5), 272; https://doi.org/10.3390/bios15050272 - 26 Apr 2025

Viewed by 101

Abstract

Bent DNA amplifying sensors were recently developed to amplify and quantify the interactions of DNA with various salts and molecules. However, a thorough quantitative understanding of their mechanism is missing. Here, using all-atom molecular dynamics (MD) simulations, we investigate the behavior and dynamics [...] Read more.

Bent DNA amplifying sensors were recently developed to amplify and quantify the interactions of DNA with various salts and molecules. However, a thorough quantitative understanding of their mechanism is missing. Here, using all-atom molecular dynamics (MD) simulations, we investigate the behavior and dynamics of sharply bent DNA molecules in the absence and presence of Mg²⁺ ions at different concentrations. The simulations show that Mg²⁺ ions reduce the fluctuations of DNA strands, enhance base-pairing, and stabilize bent DNA molecules. The computational results are further verified by both melting curve experiments and ensemble FRET measurements, highlighting the mechanical instability and sensitivity of bent DNA molecules. Full article

(This article belongs to the Special Issue DNA Molecular Engineering-Based Biosensors)

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16 pages, 8827 KiB

Open AccessArticle

One-Pot Colorimetric Nucleic Acid Test Mediated by Silver Nanoparticles for DNA Extraction and Detection

by Seung Kyun Park, Kieu The Loan Trinh and Nae Yoon Lee

Biosensors 2025, 15(5), 271; https://doi.org/10.3390/bios15050271 - 25 Apr 2025

Viewed by 167

Abstract

This study introduces a one-pot colorimetric nucleic acid test (NAT) platform that integrates silver nanoparticle (AgNP)-based DNA isolation and colorimetric detection of bacterial genes. The NAT platform is comprised with purification and reaction units that enable cell lysis, DNA purification, loop-mediated isothermal amplification [...] Read more.

This study introduces a one-pot colorimetric nucleic acid test (NAT) platform that integrates silver nanoparticle (AgNP)-based DNA isolation and colorimetric detection of bacterial genes. The NAT platform is comprised with purification and reaction units that enable cell lysis, DNA purification, loop-mediated isothermal amplification (LAMP), and colorimetric detection. In the purification unit, polyethyleneimine (PEI)-capped AgNPs were used as cell lysis agents because of their cell-disrupting and antimicrobial properties and were immobilized on a glass fiber membrane for DNA capture and isolation. The reaction unit enabled colorimetric detection of DNA amplicons, achieved by the synthesis of AgNPs on chromatography paper formed via the reduction of silver ions present on the paper, mediated by the use of sodium ascorbate, a reducing agent, present in the LAMP reagent, after the reaction. AgNPs were formed only in the presence of the target amplicons in the positive samples after reaction at 65 °C for 5 min. Bacterial DNA was efficiently extracted using this method, and Enterococcus faecium was detected with a detection limit of 10² CFU/mL. This platform is a promising alternative for rapid and cost-effective nucleic acid testing in resource-limited settings. Full article

(This article belongs to the Special Issue Micro-/Nano Biomedical Point-of-Care Devices)

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16 pages, 9379 KiB

Open AccessArticle

Activation and Expansion of Human T-Cells Using Microfluidic Devices

by Ana Belén Peñaherrera-Pazmiño, Gustavo Rosero, Dario Ruarte, Julia Pinter, Karla Vizuete, Maximiliano Perez, Marie Follo, Betiana Lerner and Roland Mertelsmann

Biosensors 2025, 15(5), 270; https://doi.org/10.3390/bios15050270 - 25 Apr 2025

Viewed by 169

Abstract

Treatment of cancer patients with autologous T-cells expressing a chimeric antigen receptor (CAR) is one of the most promising therapeutic modalities for hematological malignancy treatment. For this treatment, primary T-cell expansion is needed. Microfluidic technologies can be used to better understand T-cell activation [...] Read more.

Treatment of cancer patients with autologous T-cells expressing a chimeric antigen receptor (CAR) is one of the most promising therapeutic modalities for hematological malignancy treatment. For this treatment, primary T-cell expansion is needed. Microfluidic technologies can be used to better understand T-cell activation and proliferation. Microfluidics have had a meaningful impact in the way experimental biology and biomedical research are approached in general. Furthermore, microfluidic technology allows the generation of large amounts of data and enables the use of image processing for analysis. However, one of the major technical hurdles involved in growing suspension cells under microfluidic conditions is their immobilization, to avoid washing them out of the microfluidic chip during medium renewal. In this work, we use a multilevel microfluidic chip to successfully capture and immobilize suspension cells. Jurkat cells and T-cells are isolated through traps to microscopically track their development and proliferation after activation over a period of 8 days. The T-cell area of four independent microchannels was compared and there is no statistically significant difference between them (ANOVA p-value = 0.976). These multilevel microfluidic chips provide a new method of studying T-cell activation. Full article

(This article belongs to the Special Issue Microfluidics and Organ-on-a-Chip for Disease Modeling and Drug Screening (2nd Edition))

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14 pages, 17614 KiB

Open AccessArticle

Unraveling Charge Transfer Mechanisms in Graphene–Quantum Dot Hybrids for High-Sensitivity Biosensing

by Shinto Mundackal Francis, Hugo Sanabria and Ramakrishna Podila

Biosensors 2025, 15(5), 269; https://doi.org/10.3390/bios15050269 - 24 Apr 2025

Viewed by 187

Abstract

Colloidal quantum dots (QDs) and graphene hybrids have emerged as promising platforms for optoelectronic and biosensing applications due to their unique photophysical and electronic properties. This study investigates the fundamental mechanism underlying the photoluminescence (PL) quenching and recovery in graphene–QD hybrid systems using [...] Read more.

Colloidal quantum dots (QDs) and graphene hybrids have emerged as promising platforms for optoelectronic and biosensing applications due to their unique photophysical and electronic properties. This study investigates the fundamental mechanism underlying the photoluminescence (PL) quenching and recovery in graphene–QD hybrid systems using single-layer graphene field-effect transistors (SLG-FETs) and time-resolved photoluminescence (TRPL) spectroscopy. We demonstrate that PL quenching and its recovery are primarily driven by charge transfer, as evidenced by an unchanged fluorescence lifetime upon quenching. Density functional theory calculations reveal a significant charge redistribution at the graphene–QD interface, corroborating experimental observations. We also provide a simple analytical quantum mechanical model to differentiate charge transfer-induced PL quenching from resonance energy transfer. Furthermore, we leverage the charge transfer mechanism for ultrasensitive biosensing to detect biomarkers such as immunoglobulin G (IgG) at femtomolar concentrations. The sensor’s electrical response, characterized by systematic shifts in the Dirac point of SLG-FETs, confirms the role of analyte-induced charge modulation in PL recovery. Our findings provide a fundamental framework for designing next-generation graphene-based biosensors with exceptional sensitivity and specificity. Full article

(This article belongs to the Section Nano- and Micro-Technologies in Biosensors)

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15 pages, 2844 KiB

Open AccessArticle

Synergistic Signal Amplification via Weak Value Amplification Effect and Sandwich Structure for Highly Sensitive and Specific Real-Time Detection of CA125

by Bei Wang, Yang Xu, Han Li, Zishuo Song, Tian Guan and Yonghong He

Biosensors 2025, 15(5), 268; https://doi.org/10.3390/bios15050268 - 23 Apr 2025

Viewed by 125

Abstract

Biomolecule detection is pivotal in disease diagnosis. In this study, we present a novel aptamer–antibody sandwich module integrated with an imaging weak measurement system to enhance the sensitivity and specificity of biomolecule detection. The feasibility of this approach is demonstrated using CA125. CA125 [...] Read more.

Biomolecule detection is pivotal in disease diagnosis. In this study, we present a novel aptamer–antibody sandwich module integrated with an imaging weak measurement system to enhance the sensitivity and specificity of biomolecule detection. The feasibility of this approach is demonstrated using CA125. CA125 is a glycoprotein tumor marker widely used for ovarian cancer diagnosis and monitoring, with its level changes closely associated with disease progression. Given its clinical significance, developing highly sensitive and specific CA125 detection methods is crucial for precision medicine. The dual-recognition mechanism combines the high affinity of aptamers and the specificity of antibodies, significantly improving detection performance while utilizing antibodies for signal amplification. In the presence of CA125, the anti-CA125 aptamer immobilized on the chip surface captures the target, which is then specifically bound by the CA125 antibody, forming the aptamer–CA125–antibody complex. This interaction induces a change in the refractive index of the chip surface, which is detected by the imaging weak measurement system and ultimately manifested as a variation in light intensity in the resulting images. The method achieves the highly sensitive detection of CA125 in the 0.01 mU/mL range to 100 U/mL, with preliminary results showing a detection resolution of 3.98 μU/mL and high specificity against non-target proteins. Additionally, detecting CA125 in serum samples further validates the feasibility of the method’s applicability in complex biological matrices. The proposed method offers significant advantages, including high sensitivity, high specificity, label-free, multiplexed detection, low cost, and real-time detection, making it a promising platform for bio-molecule detection with a wide range of applications. Full article

(This article belongs to the Section Biosensors and Healthcare)

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16 pages, 2277 KiB

Open AccessArticle

Simultaneous Trace Analysis of Lead and Cadmium in Drinking Water, Milk, and Honey Samples Through Modified Screen-Printed Electrode

by Fei Wang, Xiao Peng, Ziqian Xiao, Ying Ge, Bilin Tao, Zhaoyong Shou, Yifei Feng, Jing Yuan and Liang Xiao

Biosensors 2025, 15(5), 267; https://doi.org/10.3390/bios15050267 - 23 Apr 2025

Viewed by 93

Abstract

A composite (N-rGO@ppy) of N-doped reduced graphene oxide (N-rGO) coated with polypyrrole (ppy) particles was successfully synthesized. The incorporation of N-rGO significantly mitigates the aggregation of ppy synthesized in situ, and the doped N atoms improve the conductivity of graphene oxide (GO), thereby [...] Read more.

A composite (N-rGO@ppy) of N-doped reduced graphene oxide (N-rGO) coated with polypyrrole (ppy) particles was successfully synthesized. The incorporation of N-rGO significantly mitigates the aggregation of ppy synthesized in situ, and the doped N atoms improve the conductivity of graphene oxide (GO), thereby enhancing N-rGO@ppy’s redox properties. Firstly, a glassy carbon electrode (GCE) modified with N-rGO@ppy (N-rGO@ppy/GCE) was used in combination with a bismuth film and square-wave anodic stripping voltammetry (SWASV) for the simultaneous trace analysis of Pb²⁺ and Cd²⁺. N-rGO@ppy/GCE exhibited distinct stripping peaks for Pb²⁺ and Cd²⁺, with a linear range of 1 to 500 μg L⁻¹. The limits of detection (LODs) were found to be 0.080 μg L⁻¹ for Pb²⁺ and 0.029 μg L⁻¹ for Cd²⁺, both of which are significantly below the standards set by the World Health Organization (WHO). Subsequently, the same electrochemical sensing strategy was adapted to a more portable screen-printed electrode (SPE) to accommodate the demand for in situ detection. The performance of N-rGO@ppy/SPE for analyzing Pb²⁺ and Cd²⁺ in actual samples, such as drinking water, milk, and honey, showed results consistent with those obtained from conventional graphite furnace atomic absorption spectrometry (GFAAS). Full article

(This article belongs to the Special Issue Electrochemical Sensors and Biosensors for Environmental, Health, and Food Safety Applications (Volume II))

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13 pages, 1853 KiB

Open AccessArticle

Aptamer-Based Microfluidic Assay for In-Field Detection of Salicylic Acid in Botrytis cinerea-Infected Strawberries

by Cristiana Domingues, Rafaela R. Rosa, Rodolfo G. Rodrigues, Ana Margarida Fortes, Virginia Chu and João Pedro Conde

Biosensors 2025, 15(5), 266; https://doi.org/10.3390/bios15050266 - 22 Apr 2025

Viewed by 150

Abstract

Rapid detection of plant infections is crucial for minimising crop loss and optimising management strategies, particularly in the context of climate change. While traditional diagnostic methods provide precise measurements of phytohormones such as salicylic acid (SA), a key regulator of plant defence responses, [...] Read more.

Rapid detection of plant infections is crucial for minimising crop loss and optimising management strategies, particularly in the context of climate change. While traditional diagnostic methods provide precise measurements of phytohormones such as salicylic acid (SA), a key regulator of plant defence responses, their reliance on bulky equipment and lengthy analysis times limits field applicability. This study presents a microfluidic-based aptamer assay for SA detection, enabling rapid and sensitive fluorescence-based readout from plant samples. A tailored sample pre-treatment protocol was developed and validated with real strawberry samples using HPLC measurements. The assay demonstrated a detection limit ranging from 10⁻⁹ to 10⁻⁶ mg/mL, within the relevant range for early infection diagnosis. The integration of the microfluidic platform with the optimised pre-treatment protocol offers a portable, cost-effective solution for on-site phytohormone analysis, providing a valuable tool for early infection detection and improved crop management. Full article

(This article belongs to the Special Issue Microfluidic Devices for Biological Sample Analysis)

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15 pages, 3804 KiB

Open AccessReview

Current Trends in In Vitro Diagnostics Using Surface-Enhanced Raman Scattering in Translational Biomedical Research

by Sitansu Sekhar Nanda, Dae-Gyeom Park and Dong Kee Yi

Biosensors 2025, 15(5), 265; https://doi.org/10.3390/bios15050265 - 22 Apr 2025

Viewed by 228

Abstract

Immunoassays using surface-enhanced Raman scattering (SERS) are prosperous in disease diagnosis due to their excellent multiplexing ability, high sensitivity, and large dynamic range. Given the recent advancements in SERS immunoassays, this work provides a comprehensive overview, from fundamental principles to practical applications. An [...] Read more.

Immunoassays using surface-enhanced Raman scattering (SERS) are prosperous in disease diagnosis due to their excellent multiplexing ability, high sensitivity, and large dynamic range. Given the recent advancements in SERS immunoassays, this work provides a comprehensive overview, from fundamental principles to practical applications. An mRNA sensor utilizing Raman spectroscopy is a detection method that leverages the unique vibrational characteristics of mRNA molecules to identify and quantify their presence in a sample, often achieved through a technique called SERS, where specially designed nanoparticles amplify the Raman signal, allowing for the highly sensitive detection of even small amounts of mRNA. This review analyzes SERS assays used to detect RNA biomarkers, which show promise in cancer diagnostics and are being actively studied clinically. To selectively detect a specific mRNA sequence, a probe molecule (e.g., a DNA oligonucleotide complementary to the target mRNA) is attached to the SERS substrate, allowing the target mRNA to hybridize and generate a detectable Raman signal upon binding. Thus, the discussion includes proposals to enhance SERS immunoassay performance, along with future challenges and perspectives, offering concise, valid guidelines for platform selection based on application. Full article

(This article belongs to the Special Issue Surface-Enhanced Raman Scattering in Biosensing Applications)

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